Method of flaking pitch



May 26, 1931. s: P. MILLER METHOD OF FLAKING ITCH FiledApril 6., 1929 Wa fer f Ale/762d p/ 72/7 F/ale 67M .w n M d M INVENTOR WZMAJL M ATTORNEYS Patented May 26, 1931' UNITED STATES PATENT OFFICE I STUART PKRMELEE MILLER, 01 ENGLEWOOD, NEW JERSEY, ASSIGNOR TO THE BARRETT COMPANY, OF-NEW YORK,- N.

Y, A QOBPORA'IION NEW J RSEY amnion or rnaxmc :errcn Application filed April 6,

This invention relates to a new and im' proved method of solidifying pitch and simiar substances such as certain resins, e. g; paracumarone-resin,'etc., which are brittle at; 5 lower temperatures and which become fluid at higher temperatures. More particularly this invention relates to a method producing flakes of (pitch fiomfluid pitch, e. g. coal tar pitch, an is particuarly a apted to flaking pitch of high meltin point.

. As is welfimown in the art, coal tar pitches, etc. are prepared for different uses in many degrees of hardness, running :from those which are very\soft and pliableat ordinary temperatures to those which are very hard and brittle at such temperatures. Although my invention may be applied to solidifying pitches or resins ofvarious melting points, it is of particularvalue in handling coal tar 80 pitches which areof sufliciently high melting point to be" commonly sold or used in lump or crushed form.

Pitches are manufactured by subjecting tar to heat in a still and distilling ofl the required amountof oils to yield a residue of pitch which-exists as a hot fluid mass which the softer pitches to agglomerate if made and handled .in lumps or chips in. bulk. Pitches of a melting point of 170180 F. and above are, however, commonly produced and shipped in bulk as large lumps or even more or less finely crushed products. These harder pitches are ordinarily transferred to storage tanks whilestill hot. and'fluid and allowed to cool somewhat therein and then run into bays from which they must be excavated for shipment. The cost of excavating the pitch from "bays and transferring it to suitable means for transporting it makes the use of bays expensive. The cooling of pitch by granulation in direct contact with water is sufiicient but the removal of water fromthe pitch is diflicult and expensive.

It is the purpose of my invention toover- ,comes from the process of manu acture in a magibe cooled to produce solid itch of lower 1929. Serial No. 352,990.

come the difiiculties encountered'b .these various methods of, handling pitc Although, according to my invention, the pitch. may e cooled in fact by direct contact with water, the cooling is preferably effected by indirect contact with water or other fluid cooling medium so that the pitch is produced in a dry form. The method is simple and entails little-expense. The pitch-is produced preferably in the form of thin flakes which can be handled easily. -In this form pitch may be handled as a bulk product much as coa According to this invention, itch, as it fluid heated state, may be solidified and formed directly into' flakes, or pitch which has previously'been produced in another form may be melted an converted into flake form. The invention is particularly adapted to the handling of' high melting point pitches such,

for exam le, as those very high melting point pitches w 'ch may be produced in the distillation of'tar by direct contact with .hot coal distillation gases, although the invention is 76 not limited to handling such pitches. It is particularly adapted to treating pitches of igh' melting po1nt,such as itches with a melting oint of 400 F. or big er or 350 F. or even, ower melting point itches, and is adapted to handling. all pitc es which are fluid'at' high temperatures and which, on cooling to near atmospheric temperature, are

.sufliciently brittle to be readily broken.

, Accordm to my invention the pitch ina -molten con ition is run on to the feed end of a conveyor, which is preferably a continuous metal belt. The belt is advantageously run 'leys. 'The pitchin a fluid condition is run on to the upper belt surface at the feed end of the upper-horizontal portions of the belt and the underside of this upper horizontal stretch of the belt is advantageously sprayed with'water or other coolin medium so that the heat of the pitch is rapi y removed and the pitch is solidified. The pitch is removed from the belt at or near the opposite end'of the horizontal portion of the belt. Where the belt'is run over two main pulleys, the pitch may advantageously be discharged from the belt as it passes over the pulley at the discharge end of the belt. Other means .may be employed for discharging the pitch from the belt, such as scrapers or-other sidedis'charge mea'ns. .lVhere scrapers are emplo ed, several hoppers or bins may be provi ed, positioned at different intervals along the length of the belt, so that as pitches of different melting points are produced, they may be discharged to different hop ers or bins by chain ing the position of the ischarge'device. The highest melting. point pitch which would be the first to solidify, would ordinarily be discharged into the hopper nearest the feed end of the belt, and the lowest melting point pitch would ordinarily be discharged into the hop- I slope u or down from the point at which per-nearest the discharge end of the belt.

The belt need not be horizontal. It may the pitc I lS added. The degree to which the belt may slope will depend upon a number of factors, such as rate of addition of pitch, speed of belt, width of belt temperature of pitch, temperature of cooling fluid, length of belt, melting point of pitch, etc.

The pitch in a thinly fluid condition is fed on to the moving belt .from a spout or other suitable discharge device and the rate of discharge of the pitch from the spout is co-ordinated with the rate at which the belt moves so that the pitch forms on the belt as a sheet or ribbon which may vary in thickness. Ordinarly the operation is so controlled that a thin layer of pitch is formed which will cool rapidly. As the pitch cools it becomes brittle and the pitch may shrink sufficiently to cause the ribbon of pitch on the belt to crack and form into several separate pieces. Means, such as end of the belt. In passing over this pulley and discharging t0 the hopper the pitch whichhas been cooled sufiiciently to make it brittle, is broken. The pitch is brokeninto flakes of irregular size and shape and may be collected in bins or other suitable storage means.

The invention will be described further in connection with the accompanying drawings in which 1 Fig. 1 is a plan view of the apparatus;

. Fig. 2 shows the apparatus in elevation;

Fig. 3 is an end view; and 4 Fig. 4 is a detail of the belt wiper.

may be a. steel belt, preferably of rustproot steel, or it may be Monel metal, bronze, etc.

In the drawings, 5 indicates the belt which I The high heat conductivity of the metal facilitates thecooling of the pitch which is spread on the belt. The belt is supported on the pulley members 6 and 7. p The pulley 7 is driven by the motor 8, thru a suitable transmission 9. Thepulley- 6 is rotatably mounted on a suitable shaft supported by the frame-,

work 10,-which is adapted to slide upon the bases. 11. The frame-work is connected to the counter-weight 12 by the cable-13 which works over the pulley 14. By proper weighting of the counterweight the proper tension is always maintained upon the belt. Expansion and contraction of the metal belt are compensated for by movement of the framework 10 upon the bases 11.

The lower portion of the belt is supported by idlers 15 mounted in suitable journal boxes inthe supports 16.

The upper portion of the belt is maintained level by the idlers 17 suitably mounted in bearings 18 which may, for example, be supported outside of the trough 19 as shown in Fig. 3.

Vith the trough are sprays 2O supplied with water from the line 21' and directed against the under-side of the upper portion of the belt. Instead of water any other suitable cooling or refrigerating-medium may be employed. The trough serves to confine, and also to collect, the spray, that portion which is not volatilized being collected in the bottom of the trough and drained ofi thru the pipes 22.

The pitch is run on to the belt from th I pitch trough 23. The trough may be provided with a jacket 23' as shown in Fig. 3, which serves to insulate the trough, or means may be provided for circulating a hot gas thruthe jacket where this is necessary to insure that the pitch is brou ht to the belt in a thinly fluid condition. The flow of pitch and the speed of travel of the belt are advantageously adjusted 'so that the pitch spreads upon the belt in a relatively thin layer. The rate at which the pitch is fed to the belt and the rate at which the belt travels and the length of the belt and the cooling action are so controlled that the pitch is chllled and brought into such a brittle condition before leaving the belt that it is easily frac tured. The drawing shows a hopper 24 for collecting the pitch as it is discharged from the belt as the belt asses around the pulley 7.

The pitch may be as the discharge means may be provided for remov-' ing the pitch from the belt before it reaches the pulley 7. Such means may comprise a collected from the belt elt passes over the pulley 7 or side 1 Iii scraper positioned at an angle'of 45 t the direction of travel of the belt. As the pitch comes in contact with such a scraper it will be discharged from the side of the belt.

In order to prevent water used for cooling the belt from collecting in the -hopper together with the pitch, wipers 26 are advantageously provided to remove adhering particles of water from the under-side of the belt before it reaches the pulley 7. These wipers may comprise rubber strips 26 held in a slot in the pipe 27. The water which is removed from the belt by these wipers is collected in the trough 19 and drains thru the outlets 22 with other-excess water from the sprays.

In a typical case pitch from coke oven tar having a melting oint of about 400 F. was delivered to the be t at a temperature of about 350 C. and was allowed to' spread freely thereon. The width of the belt was about 18" and the distance from the point at which the pitch came onto the belt and the point. at which it was discharged from the belt was about 57 feet. The drivin mechanism was regulated so that the spec of travel of'the beltwas about fifty feet per minute. This gave a cooling period of'about sixty-eight seconds and under these conditions the pitch which, when cooled, gave a flake about onetenth of an inch thick, was chilled and cracked to some extent on the belt and was broken into small flakes as it fell from the conveyor and was collected in the hopper.

Thin, small, brittle flakes of pitch were obtained. The belt handled in theneighborhood of 160 gallons of pitch per hour.

The length of the belt ma be varied to pro vide more or less cooling 0 the pitch and the rate at which the belt travels ma also be controlled to regulate the length 0 time during which the pitch is held on the belt. Various-- means for cooling the belt with air coolers and other cooling devices may be employed but spraying the underside of the belt with water will be suflicient to provide the cooling required to solidify hardpitches. The tem: perature to which the pitch must be cooled before being discharged from the belt de-' erally be preferredto one broader sheet of the and several separate streams-of pitch may be 7 run'on to the belt in such a way as to form several separate parallel ribbons of pitch on the single belt. I

The apparatus herein described is simple and the operation is also simple. There are no complicated units and the method of operation is free from involved steps. The cost of installing such a pitch-flaking apparatus is small and the cost ofoperating it is not large. The invention provides a method of producing smallparticles of hardened pitch without the necessity of grinding or otherwise comminuting large lumps or chunks, and is desirable for this and other reasons.-

This application is in parta continuation of my .oo-pending application Serial No. 227,927, filed October 22,1927.

I claim:

The method of flaking pitch which corn; prises'discharging the pitch in'the-form of a lot molten stream, forming the said stream into a ribbon-like thin layer, subjecting one side of the layer to a cooling mediumuntil it is sufl'iciently brittle to be readily broken and then breaking said ribbon-like layer of pitch and causing said resulting fragments to drop whereby they will be brokeninto flakes as they fall onto the receiving means. I

In testimony whereof I aifix my signature. STUART PAItMELEE MILLER.

pends upon the melting point of the pitch; "higher melting point p1tches become solid at higher temperatures, and lower melting point pitches require cooling to lower temperatures 1 in order to effect solidification.

The pitch is ordinarily fed onto the con- -Veyor in such a way as to form a thin layer of the pitch. Ordinarily a relatively narrow ribbonof the itch is formed inorder that the pitch on soli ifying will readily break into small chips or flakes. A wider ribbon or sheet of adjacent sources. Various means of forming such awider sheetofthepitch may be devised.

itch may be formed by allowing pitch to ow on to the same belt from'severa 

